Study on metal accumulation in aquatic plants of Cuciurgan cooling reservoir

The biomass of plants from the Cuciurgan cooling reservoir of the Moldovan Thermal Power Plant is dependent on the reservoir thermofication and bore considerable modifications. The contents of many metals in aquatic plants were highly correlated with their contents in water: r=0,87-0,91. The dynamics of trace element accumulation depends on seasonal factors. From the beginning of spring to the end of summer and beginning of autumn, the concentrations of trace elements increased by large increments, while with the decrease in temperature below 10°C, an opposite effect was observed. After plant death, a significant part of accumulated trace elements are released into the water, in the most cases this being associated with organic compounds. More than one half of the amount of trace elements is deposited with the decaying plants in the bottom sediments. Therefore, difficulties may arise, while identifying the role of aquatic plants in biogenic migration of metals in aquatic ecosystems and water purification processes.